Hi, I just bought a bag of usb-serial converters off of ebay, from china for super low price (~$2/each). I just plugged a couple of them in, connected together through a null-modem adapter. When I plug them, on both stock ubuntu 16.04's kernel and 4.8.9 built from git, I get a reasonable looking dmesg: [822616.501963] usb 2-2.3: new full-speed USB device number 16 using xhci_hcd [822616.602985] usb 2-2.3: New USB device found, idVendor=1a86, idProduct=7523 [822616.602988] usb 2-2.3: New USB device strings: Mfr=0, Product=2, SerialNumber=0 [822616.602989] usb 2-2.3: Product: USB2.0-Ser! [822617.633618] usbcore: registered new interface driver usbserial [822617.633638] usbcore: registered new interface driver usbserial_generic [822617.633653] usbserial: USB Serial support registered for generic [822617.638736] usbcore: registered new interface driver ch341 [822617.638755] usbserial: USB Serial support registered for ch341-uart [822617.638770] ch341 2-2.3:1.0: ch341-uart converter detected [822617.640272] usb 2-2.3: ch341-uart converter now attached to ttyUSB0 [822625.294363] usb 2-2.2: new full-speed USB device number 17 using xhci_hcd [822625.395324] usb 2-2.2: New USB device found, idVendor=1a86, idProduct=7523 [822625.395327] usb 2-2.2: New USB device strings: Mfr=0, Product=2, SerialNumber=0 [822625.395328] usb 2-2.2: Product: USB2.0-Ser! [822625.396487] ch341 2-2.2:1.0: ch341-uart converter detected [822625.397575] usb 2-2.2: ch341-uart converter now attached to ttyUSB1 I attach the tty's with GNU screen (but I have also tried microcom and minicom with the same results). This was my first experience with or even awareness of ch341. I have much more experience with pl2303 and somewhat less with ftdi. With these ch341, when I type in an 'a' on one terminal, I get 0x01 out the other terminal. If I type in a 'b', I get an 0x02, etc, on up to 'z' yielding 0x1a. I found your name/contact in the git commits. Any idea what is going on? My leading theory at the moment is that the manufacturer didn't populate all the parts, and the vendor got an great deal on them, which they passed on to me! -- Russell Senior, President russell@xxxxxxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
